Abstract: The dynamic change of species diversity and the assessment of population status are very important for the scientific conservation of species. The eastern margin of Qinghai-Tibet Plateau is a global biodiversity hotspot in southwest China, which has important scientific research value and conservation status. In order to effectively evaluate the diversity and distribution pattern of large- and medium-sized mammals in the eastern Qinghai-Tibet Plateau, Xinlong County, which is the most representative county in this region, was selected as the main research area. The literatures and data related to infrared cameras published in this region since 2013 were systematically collected, and an infrared camera survey was carried out from December 2019 to October 2020. The results showed that there were at least 36 species of mammals in Xinlong County, belonging to 5 orders, 14 families, including 7 species of cats, 7 species of national level I and 16 species of national Level II key protected wild animals. According to the IUCN Red List, there were two species of endangered (EN), seven species of vulnerable (VU) and six species of near threatened (NT). During the monitoring and research over the years, Carnivore and Cetartiodactyla species were abundant, and 7 cats were still recorded at an interval of nearly 3 years. The relative abundance index (RAI) and grid occupancy (GO) of Leopard (Panthera pardus) ranked among the top 10. The relationship between the size of RAI and GO of seven cats was as follows: Leopard > Leopard Cat (Prionailurus bengalensis) > Eurasian Lynx (Lynx lynx) > Snow Leopard (Panthera uncia) > Asiatic Golden Cat (Catopuma temminckii) > Chinese Mountain Cat (Felis bieti) = Pallas's Cat (Felis manul). In this study, it was found that in different habitats and at different altitudes in different seasons, a variety of cats and main prey species were distributed, and the five cats except Chinese Mountain Cat and Pallas's Cat had different degrees of overlap with their main prey and disturbance factors in different seasons. The results of this study indicated that the overall population status of cats in Xinlong County on the eastern Qinghai-Tibet Plateau was good, food resources were abundant, and the entire ecosystem was in a healthy state. However, it is necessary to further strengthen the scientific control of disturbance factors in the main distribution areas of cats in the future. At the same time, the difficulties faced by the protection of rare and endangered wild animals represented by cats in Xinlong County were also pointed out, and the follow-up protection suggestions were put forward for reference.